LOS ANGELES, California (CNN) --A leaked memo from the Los Angeles Department of Children and Family Services concludes that allegations of sexual abuse of a young boy by pop superstar Michael Jackson were "unfounded."

But Santa Barbara District Attorney Tom Sneddon, who announced he will formally charge the entertainer by sometime next week, said he was "discounting" the memo, which was posted Tuesday on the "Smoking Gun" Web site.

According to the November 26 memo, the mother felt "the entertainer was like a father to the children and part of her family."

Sneddon confirmed she was referring to Jackson.

The memo, which was written in response to a request and summarizes an investigation conducted between February 14-27, concerns the young cancer patient on whose behalf Sneddon's office is prosecuting Jackson.

The memo said the child -- now 14 -- denied he slept in the same bed as Jackson or that any sexual abuse had ever occurred. It also indicates the boy's older sister said she had accompanied her brothers to numerous sleepovers at Jackson's Neverland Ranch and "had never seen anything sexually inappropriate between her brother and the entertainer."

"Our investigators were aware of the contents of the memo prior to seeking the search warrants and arrest warrant for Mr. Jackson," Sneddon said.

"We provided all the information to the judge about the circumstances and the timing of the child welfare investigation, and the judge still issued the warrants," he said.

Asked if the leaked memo that appears to exonerate Jackson hurts his case, Sneddon replied, "No, we are not worried."

A Jackson spokesman told CNN the leaked memo supports his innocence.

"There is no merit to the allegations, Michael is innocent," said Stuart Backerman. "This is in keeping with what we've said all along."

The L.A. child welfare agency got involved because the alleged victim is a county resident.

The 45-year-old singer returned to Santa Barbara, California, from Las Vegas, Nevada, to surrender to authorities November 20, was booked on charges of "lewd and lascivious conduct" with a child under 14, and released on $3 million bond.

If the formal charges are filed next week, he will be arraigned January 9.